The applicant proposes to investigate the acute and chronic effects of ethanol (EtOH), acetaldehyde (ACA), and tetrahydroisoquinoline alkaloids (TIQs) on cardiac functions in normotensive and hypertensive rats. The project consists of three specific aims in which the effects of EtOH, ACA, and tetrahydropapaveroline (THP) will be examined on the automaticity and 1) membrane potentials of rat sinus mode, 2) the electromechanical function of isolated ventricular papillary muscle and 3) calcium mobilization in isolated rat ventricular myocytes. THP forms in the CNS during the metabolism of dopamine in the presence of EtOH, and since it closely resembles morphine in structure, it is assumed that THP might mediate the addictive properties of alcohol.